In mid-December, antibiotic resistant Citrobacter freundii was found in blood cultures taken from the three infants prior to their deaths at the Ewha Womans University Mokdong Hospital, and their genetic sequence was found to be identical several days later.

A week later, KCDC announced that the same bacteria was confirmed in the administered total parenteral nutrition (TPN) injections, which is given to infants who have trouble eating to provide necessary nutrients.

Five out of 16 infants received the injections, resulting in four deaths.

The injections were administered using a central venous line, suggesting the possibility that they had been contaminated in their preparation.

“Combining the results of the epidemiological investigation by the Korea Centers for Disease Control and Prevention and those of the autopsies by the National Forensic Service, we have concluded that the four newborns died of sepsis, caused by an infection with Citrobacter freundii,” the Seoul Metropolitan Police Agency said.

The police said they would book five medical staffs on charges of involuntary manslaughter. The two nurses allegedly infringed on the duty of infection control while handling the injection of nutrient supplements. A chief nurse, a specialist, and an attending physician reportedly breached the duty of guide and supervision of the two nurses.

In addition, rotavirus was confirmed in environmental samples (incubator, blankets, etc.) from the NICU and samples from nine of the 12 infants. Eight of the nine viruses had the same genetic sequence (one pending). KCDC is closely monitoring the condition of the infants.